How would the events which took place in ''Lord of the Flies'' influence Ralph's life 20 years later?
Hemingway wrote that the sense of the tragic is in the minds of all thinking men. In Chapter 5 Ralph has the epiphany of realizing that "thought was a valuable thing, that got results...." Ralph is a "specialist in thought" after this epiphany and "recognizes thought in another."
As an adult Ralph could become much like Hemingway's characters such as Nick and others who have a sense of the tragic. To create order in their worlds, they themselves must establish it, for there really is none otherwise. As a thinking man, Ralph might experience much of the post World War II disillusionment and become, perhaps, like Hemingway, part of the "Lost Generation." establishing order only through his personal efforts in his personal life. For, he has met the Rogers who "carried death in his hands."
He would probably be haunted by dreams of people chasing him with spears and torches. Of course, he could either be a raving lunatic who loses himself in illegal substances to forget his horrible past, or he could channel this anger and frustration into counseling others or being a motivational speaker to help others avoid getting themselves in that sort of situation.
What an interesting question. If Ralph survived the atomic war he was about to return to at the end of the novel, I think that, as he matured, the experience on the tropical island would have taught him many lessons. Many great men's careers have begun with failure, from George Washington and Winston Churchill to even Barack Obama and his efforts to be a community organizer, were all failures at the beginning. However, each man learned from his mistakes and used them later to turn his failures into successes. Hopefully, Ralph would be the same. As he grew older, he would realize that placating Jack and giving him power to be the lead hunter, only increased Jack's desire for power. Ralph would also realize that things don't simply "fall into place" when one is in a leadership position. He expected the boys to follow him simply because he was the leader. He did not take time to really establish a power base or any consequences for not following him. He did not listen to Piggy or to Simon, who could have been his wisest advisors. As Ralph matured, if he understood his first failure at leadership, he would have been in an outstanding place to become a very effective leader.
I don't know that Ralph would have been positively affected by these events at all, at least I don't know if that's how Golding wrote it. The major affect Ralph experiences by the end of the story is his new found knowledge of the "darkness of man's heart," which he weeps for on the very last page. This knowledge above all is what he probably would leave the island with. Since Golding does not resolve the story with anything but harsh realism concerning humanity as he has Ralph learn this lesson, I could picture Ralph turning into an adult similar to Marlow from Joseph Conrad's "Heart of Darkness," a man who has also looked into the darkness of man's hearts and subsequently become fairly cynical.